Mad Stalker All robots in story mode
At the title screen, press Up, Down, Left, Right, X, Circle.
All robots in versus mode
Enable the “All robots in story mode” code, then return to the title screen. Now press Up, Down, Left, Right, Up, Down, Left, Right, Up, Down, Left, Right, X, Circle.
The image featured at the top of this post is ©The Legend of Heroes: Trails of Cold Steel III key art / Original